LOCKPORT, N.Y. -- A Niagara Falls teenager faces 20 years to life in prison for killing a 5-year-old girl he was babysitting.

John Freeman Jr. is scheduled to be sentenced in Niagara County Court Thursday afternoon. He pleaded guilty in July to charges of second-degree murder and evidence tampering.

Authorities say the 17-year-old killed Isabella Tennant at the girl's great-grandparents' home in Niagara Falls in August 2012. Isabella was spending the night there while her mother worked. Freeman was a neighbor of the homeowners, who said they left the girl in his care when they went to bed.

Investigators say Freeman disposed of Isabella's body in a garbage container with the help of an 18-year-old friend.